import { getSession, requestJson } from '@/services/api.uts'

export type UserMessage = { id: string, type: string, category: string, icon: string, title: string, content: string, time: string, isRead: boolean }
export type MessagePage = { items: UserMessage[], snapshotId: string, nextBeforeId: string, unreadCount: number }
export type MessageDetail = { item: UserMessage, targetUrl: string, targetLabel: string, targetUnavailable: boolean }

const validId = (value: string, allowZero: boolean): boolean => {
    if (!(allowZero ? /^(?:0|[1-9][0-9]{0,9})$/.test(value) : /^[1-9][0-9]{0,9}$/.test(value))) return false
    return !(value.length == 10 && value > '2147483647')
}
const requiredId = (value: string, message: string): string => {
    if (!validId(value, false)) throw new Error(message)
    return value
}
const requiredText = (data: UTSJSONObject, key: string, message: string): string => {
    const value = data.getString(key)
    if (value == null || value.length == 0) throw new Error(message)
    return value
}
const parseSnapshotId = (value: string): string => {
    if (!validId(value, true)) throw new Error('消息快照格式无效')
    return value
}
const optionalId = (value: any | null): string => {
    if (value == null) return ''
    if (typeof value != 'string') throw new Error('消息分页游标格式无效')
    if (value.length == 0) return ''
    return requiredId(value as string, '消息分页游标格式无效')
}
const count = (data: UTSJSONObject): number => {
    const value = data.getNumber('unreadCount')
    if (value == null || !Number.isInteger(value) || value < 0) throw new Error('未读数量格式无效')
    return value
}
function messageFrom(data: UTSJSONObject): UserMessage {
    const id = data.getString('id') ?? ''; const type = data.getString('type') ?? ''
    if (!validId(id, false) || !['system', 'service', 'activity'].includes(type)) throw new Error('消息格式无效')
    const title = requiredText(data, 'title', '消息标题格式无效')
    const content = requiredText(data, 'content', '消息内容格式无效')
    const createdAt = requiredText(data, 'createdAt', '消息时间格式无效')
    const isRead = data.getBoolean('isRead')
    if (isRead == null) throw new Error('消息已读标记无效')
    const categories: UTSJSONObject = { system: '系统通知', service: '服务通知', activity: '活动消息' }
    const icons: UTSJSONObject = { system: 'system-bell', service: 'approval', activity: 'gift' }
    const date = new Date(createdAt.replace(' ', 'T'))
    const now = new Date(); const pad = (n: number): string => n < 10 ? '0' + n.toString() : n.toString()
    let time = '未记录'
    if (!isNaN(date.getTime())) time = date.getFullYear() == now.getFullYear() && date.getMonth() == now.getMonth() && date.getDate() == now.getDate()
        ? pad(date.getHours()) + ':' + pad(date.getMinutes()) : date.getFullYear().toString() + '-' + pad(date.getMonth() + 1) + '-' + pad(date.getDate())
    return { id, type, category: categories.getString(type) ?? '', icon: icons.getString(type) ?? '', title,
        content, time, isRead }
}
export async function fetchUnreadMessages(): Promise<number> {
    if (getSession() == null) return 0
    return count(await requestJson('/messages/unread-count', 'GET', {}))
}
export async function fetchMessages(type: string, beforeId: string = '', snapshotId: string = ''): Promise<MessagePage> {
    if (!['all', 'system', 'service', 'activity'].includes(type)) throw new Error('消息分类无效')
    if (beforeId.length > 0 && !validId(beforeId, false)) throw new Error('消息分页游标格式无效')
    if (beforeId.length > 0 && snapshotId.length == 0) throw new Error('消息分页快照缺失')
    if (snapshotId.length > 0 && !validId(snapshotId, true)) throw new Error('消息快照格式无效')
    const params: UTSJSONObject = { type, limit: 20 }
    if (beforeId.length > 0) { params['beforeId'] = beforeId; params['snapshotId'] = snapshotId }
    const data = await requestJson('/messages', 'GET', params)
    const rows = data['items']
    if (rows == null || !Array.isArray(rows)) throw new Error('消息列表格式无效')
    ;(rows as any[]).forEach((item: any) => {
        if (item == null || typeof item != 'object' || Array.isArray(item)) throw new Error('消息列表格式无效')
    })
    const returnedSnapshot = parseSnapshotId(data.getString('snapshotId') ?? '')
    return { items: (rows as UTSJSONObject[]).map((item: UTSJSONObject): UserMessage => messageFrom(item)), snapshotId: returnedSnapshot,
        nextBeforeId: optionalId(data['nextBeforeId']), unreadCount: count(data) }
}
export async function fetchMessage(id: string): Promise<MessageDetail> {
    if (!validId(id, false)) throw new Error('消息编号无效')
    const data = await requestJson('/messages/' + id, 'GET', {})
    const item = data['item']
    if (item == null || typeof item != 'object' || Array.isArray(item)) throw new Error('消息详情格式无效')
    const targetValue = data['target']
    if (targetValue != null && (typeof targetValue != 'object' || Array.isArray(targetValue))) throw new Error('消息关联格式无效')
    const target = targetValue as UTSJSONObject | null
    let targetUrl = ''; let targetLabel = ''
    if (target != null) {
        const kind = target.getString('kind') ?? ''
        if (kind == 'feedback') {
            const feedbackId = requiredId(target.getString('feedbackId') ?? '', '关联反馈格式无效')
            targetUrl = '/packages/content/help/help?feedback=1&feedbackId=' + feedbackId; targetLabel = '查看回复'
        } else {
            const assessmentId = target.getString('assessmentId') ?? ''; const revisionId = target.getString('revisionId') ?? ''
            const type = target.getString('type') ?? ''
            if (!validId(assessmentId, false) || !validId(revisionId, false) || !['personal', 'enterprise'].includes(type)) throw new Error('关联评估格式无效')
            // 只构造白名单路由，通知不能下发任意链接；历史失败也只打开原提交版本。
            if (kind == 'report') { targetUrl = '/packages/finance/report/report?assessmentId=' + assessmentId + '&revisionId=' + revisionId; targetLabel = '查看报告' }
            else if (kind == 'revision') { targetUrl = '/packages/finance/archive/archive?assessmentId=' + assessmentId + '&revisionId=' + revisionId + '&type=' + type; targetLabel = '查看评估' }
            else throw new Error('关联评估格式无效')
        }
    }
    const targetUnavailable = data.getBoolean('targetUnavailable')
    if (targetUnavailable == null) throw new Error('消息关联状态无效')
    return { item: messageFrom(item as UTSJSONObject), targetUrl, targetLabel, targetUnavailable }
}
export async function readMessage(id: string): Promise<number> { return count(await requestJson('/messages/' + id + '/read', 'POST', {})) }
export async function readAllMessages(snapshotId: string): Promise<number> {
    if (!validId(snapshotId, true)) throw new Error('消息快照格式无效')
    const data = await requestJson('/messages/read-all', 'POST', { snapshotId })
    const updatedCount = data.getNumber('updatedCount')
    if (updatedCount == null || !Number.isInteger(updatedCount) || updatedCount < 0) throw new Error('消息已读回执格式无效')
    const returnedSnapshot = parseSnapshotId(data.getString('snapshotId') ?? '')
    if (returnedSnapshot != snapshotId) throw new Error('消息已读回执快照不一致')
    return count(data)
}